It is the purpose of this research project to continue to develop experimental designs and methods of statistical analysis applicable to dental and oral research problems. Many of the designs elaborated in the past have been concerned with therapeutic trials, particularly in the field of dental caries. We propose to continue to elaborate appropriate designs and analyses for therapeutic trials, particularly in the field of dental caries, but also in the area of oral biology. We expect to devote considerable attention to the appropriateness of the multivariate techniques for certain types of designs handled routinely in the past by analysis of variance models. The emphasis of multivariate analysis is more feasible now than previously, in view of high-speed computer facilities. These methods have definite applications to practical problems in clinical trials in dental caries.